I targeted a sub with my pirate that was far away (good way to make a quick way across a map w/o other fast units BTW!) but my target went out of visibility range.
My time machine says my sub will turn around immediately, but the sub won't turn off it's course.
Check it out:
Pirate is moving towards a target no longer visible. I can waypoint it back towards my territory (you can see the dotted waypoint line) but it won't stop moving towards a target it can no longer see:
Pirate showing 12 hours before it reaches where the target disappeared (although it's clearly not on that course)
But, time machine says the sub will turn around immediately:
Time machine showing that the sub hasn't actually turned around in the last 4 hours.